216321720 has 64 divisors (see below), whose sum is σ = 669911040. Its totient is φ = 55824000.

The previous prime is 216321713. The next prime is 216321757. The reversal of 216321720 is 27123612.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 25356 + ... + 32795.

It is an arithmetic number, because the mean of its divisors is an integer number (10467360).

Almost surely, 2^216321720 is an apocalyptic number.

216321720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

216321720 is an abundant number, since it is smaller than the sum of its proper divisors (453589320).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

216321720 is a wasteful number, since it uses less digits than its factorization.

216321720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58196 (or 58192 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 24.

The square root of 216321720 is about 14707.8795208555. The cubic root of 216321720 is about 600.2977411148.

The spelling of 216321720 in words is "two hundred sixteen million, three hundred twenty-one thousand, seven hundred twenty".